SOMATOSENSORY AND AUDITORY EVOKED-POTENTIAL STUDIES OF FUNCTIONAL DIFFERENCES BETWEEN THE CEREBRAL HEMISPHERES IN PSYCHOSIS

  • 1 January 1979
    • journal article
    • research article
    • Vol. 14  (2) , 357-373
Abstract
Evidence of lateralized hemispheric dysfunction in schizophrenia was previously found with a measure of visual evoked potential (VEP) wave-shape stability. The purpose of this study was to determine whether the VEP findings would extend to the auditory and somatosensory modalities. Measures of wave-shape stability were computed for auditory (AEP) and somatosensory (SEP) evoked potentials, recorded from 1 EOG [electrooculogram] and 14 scalp leads. Subjects were 74 unmedicated patients (49 schizophrenics, 25 nonpsychotics) and 27 nonpatients; 2 sets of age- and sex-matched comparison groups were formed. Overtly psychotic schizophrenics exhibited lower than normal stability in left hemisphere AEP (15-100 ms poststimulus). Both overtly psychotic and latent schizophrenics showed lower than normal wave-form stability, bilaterally, in the later epoch of AEP (101-450 ms poststimulus). A subgroup of overt schizophrenics (other than chronic paranoid or chronic undifferentiated) had lower than normal stability in SEP (15-100 ms) evoked by right median nerve stimuli and recorded from the right (ipsilateral) hemisphere. Only the AEP results augment the previous VEP evidence indicating left hemipshere involvement in schizophrenic dysfunction.